For one thing, Apple's already announced what's coming: iCloud, Lion and iOS 5

Apple did something really unusual this week: It pre-announced what it's going to talk about next week at its big Worldwide Developers Conference (WWDC). For many companies, talking up new products, technology road maps, earnings estimates and overall plans is standard operating procedure. For Apple, it's unheard of. The company always keeps its plans quiet until they're actually announced -- even if most Apple watchers have some idea beforehand. That's what allows Apple CEO Steve Jobs to offer up his signature "one more thing" when he speaks.

No doubt, the company is looking to manage expectations. Apple events always create a lot of hype. This year, however, Apple wants to tamp down any expectations of a new iPhone or some other hardware. It's also priming the pump a bit. While the iCloud streaming music service is something most Apple watchers have been expecting, iOS 5 hasn't been on the radar -- partly because Apple usually announces iOS updates in lockstep with new iPhones. And since Mac OS X 10.7 "Lion" is due out this summer, it's a natural topic to highlight.

Apple could also be trying to simply remind everyone that WWDC isn't really about hardware. It's a developer conference and training ground first, and an Apple media event second. That means its real focus should be on operating system and software updates.

And certainly, reminding people that Jobs will be at the keynote helps generate attention for the show. Yes, he is still on medical leave. But announcing that he'll be at the event is tantamount to saying he's still relatively healthy and involved. (Not surprisingly, Apple's stock price ticked up on the news Tuesday.)

I think one of the biggest things to keep in mind about WWDC 2011 is that it is a developer event and that it has returned to its traditional focus after last year's iOS-only approach. This means that there will be both Mac and iOS development tracks, as well as an enterprise technology track.

Yes, despite the assumption that Apple largely ignores the enterprise market, it does include some very in-depth Mac/iOS enterprise integration sessions at WWDC -- and the fact that Apple has reinstated that track indicates that the company still has its eye on the enterprise, even after canceling the Xserve.

Here's what to look for from next week's big show.

iCloud

The biggest buzz this year is about iCloud and how it will be a streaming iTunes service/locker like those already announced by Amazon and Google. The big difference is that Apple has been working to secure streaming agreements from the major music labels, while Amazon and Google pretty much gave up on doing so and launched their services without label approval or cooperation.

This difference frees Apple from the kind of legal battle with the labels and Recording Industry Association of America that Amazon and Google now likely face. More important, it will probably obviate the need for a service that is solely locker-based.

Both Amazon and Google require you to upload your existing music library. Without any license agreements, they have to do this because they can only share files that you already own. (Amazon will place a copy of new purchases into your locker automatically, however.) Most of us, however, have music libraries that are in the tens or hundreds of gigabytes in size. That's a lot to upload -- something that could take days or weeks to do, depending on your Internet connection.

With label approval, Apple can just use a list of music that you own and stream files that already exist on its iTunes servers. Only your iTunes database needs to be uploaded. The various iTunes database and XML files on my Mac total around 20MB. That's a much shorter upload, and Apple probably needs only the iTunes Music Library database and/or iTunes Music Library XML files. In fact, if you've turned on the iTunes Genius feature, Apple likely has all the data it needs to stream music from its servers.